Commit 35fad98e authored by Jiri Slaby (SUSE)'s avatar Jiri Slaby (SUSE) Committed by Greg Kroah-Hartman
Browse files

serial: meson+qcom: don't advance the kfifo twice 



Marek reports, that the -next commit 1788cf6a (tty: serial: switch
from circ_buf to kfifo) broke meson_uart and qcom_geni_serial. The
commit mistakenly advanced the kfifo twice: once by
uart_fifo_get()/kfifo_out() and second time by uart_xmit_advance().

To advance the fifo only once, drop the superfluous uart_xmit_advance()
from both.

To count the TX statistics properly, use uart_fifo_out() in
qcom_geni_serial (meson_uart_start_tx() already uses that).

I checked all other uses of uart_xmit_advance() and they appear correct:
either they are finishing DMA transfers or are after peek/linear_ptr
(i.e. they do not advance fifo).

Signed-off-by: default avatarJiri Slaby (SUSE) <jirislaby@kernel.org>
Reported-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Fixes: 1788cf6a ("tty: serial: switch from circ_buf to kfifo")
Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Link: https://lore.kernel.org/r/20240416054825.6211-1-jirislaby@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b20172ca

drivers/tty/serial/meson_uart.c

+0 −1
Original line number Diff line number Diff line
@@ -162,7 +162,6 @@ static void meson_uart_start_tx(struct uart_port *port) 
			break;



		writel(ch, port->membase + AML_UART_WFIFO);

		uart_xmit_advance(port, 1);

	}



	if (!kfifo_is_empty(&tport->xmit_fifo)) {

drivers/tty/serial/qcom_geni_serial.c

+1 −3
Original line number Diff line number Diff line
@@ -855,7 +855,6 @@ static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport, 
					     unsigned int chunk)

{

	struct qcom_geni_serial_port *port = to_dev_port(uport);

	struct tty_port *tport = &uport->state->port;

	unsigned int tx_bytes, remaining = chunk;

	u8 buf[BYTES_PER_FIFO_WORD];
@@ -863,8 +862,7 @@ static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport, 
		memset(buf, 0, sizeof(buf));

		tx_bytes = min(remaining, BYTES_PER_FIFO_WORD);



		tx_bytes = kfifo_out(&tport->xmit_fifo, buf, tx_bytes);

		uart_xmit_advance(uport, tx_bytes);

		tx_bytes = uart_fifo_out(uport, buf, tx_bytes);



		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);